1. Field of the Invention
This invention relates to a laser beam scanning radiating apparatus. This invention particularly relates to a laser beam scanning radiating apparatus, which is of the external resonator type and has no mechanical movable part.
2. Description of the Prior Art
Lasers have heretofore been used as scanners, and the like, in various fields in order to read out information from media, on which the information has been recorded, or to record information on recording media.
In the laser used as the scanner, a laser beam is radiated in a single predetermined direction from the laser apparatus. The laser beam, which has been radiated out in the predetermined direction, impinges upon a scanning system, such as a rotating polygon mirror or a light deflector utilizing a galvanometer mirror, and is reflected to the direction in accordance with the direction of rotation of the rotating polygon mirror or the direction of deflection of the light deflector. In this manner, the laser beam is scanned. Ordinarily, the scanning is carried out in one-dimensional direction. Also, when necessary, the scanning is carried out in two-dimensional directions by combining the one-dimensional scanning system and a different scanning system, which carries out the scanning in a direction different from the scanning direction of the one-dimensional scanning system.
However, with the conventional scanning system, which is provided with mechanical movable parts, such as the rotating parts, the scanning stability is limited to a certain level, and it is not always possible to keep the scanning accuracy high while the scanning speed is being kept high. Also, with a single scanning system, only the one-dimensional scanning can be carried out, and the scanning in two-dimensional directions or in more directions cannot be carried out. Further, in cases where a plurality of laser beams respectively radiated out of a plurality of laser beam sources are scanned simultaneously such that a large amount of scanning light may be obtained, it is necessary to use modulating devices, and it is difficult to accurately control the space between the laser beams, or the like.